The manufacture of an armature for an electric motor typically begins with the formation of an armature subassembly including a commutator and a laminated core mounted on an armature shaft with appropriate insulating sleeves between the core and the commutator and between the opposite ends of the armature shaft and the core and the commutator. The commutator has plural bars, each of which has a coil lead wire-receiving portion, such as a hook-like tang or a slot. The core has outwardly opening, coil-receiving slots, insulating laminations or coatings at each end of the core, and insulators lining the coil-receiving slots. The armature subassembly thus formed is loaded into an armature winder which winds coils of insulation-coated magnet wire into the core slots and connects coil leads extending to and from the coils to the lead wire-receiving portions of the commutator bars. Following completion of the winding and lead-connecting operations, the armature subassembly is removed from the armature winder and transferred to a machine known as a fuser or hot staker which permanently connects the coil leads to the commutator bars by application of heat and pressure to the commutator bars which burns off the insulating coating from the magnet wire in the areas of the connections to the commutator bars and fuses the commutator bars and wire leads together.
For purposes of the following specification including the claims, the term "armature", including both singular and plural forms, is used to refer to unwound armature subassemblies described above as well as to wound subassemblies and to wound and fused subassemblies, unless a contrary usage is evident.
Armatures often have to be produced in vast quantities at low costs and there is always a need for low cost yet reliable methods and apparatus for manufacturing armatures at a high rate of speed. This need has led to the development of armature manufacturing lines having conveyors for transporting unwound armatures to armature winding machines, then to fusers and then to unload stations or to other processing stations, such as wedge inserting, balancing and testing stations. Conveyors used in these procedures include simple inclined supply tracks, chain conveyors, or pallet conveyors of varying degrees of sophistication. Various armature handling devices, such as elevators and transfer or loading and unloading devices are used at the several processing stations for presenting the armatures to the processing machines and for removing the armatures from the processing machines.
Armature manufacturing apparatus have been used which have a rotating turret plate upon which are mounted armature loading and unloading devices that operate to grip an unwound armature lifted off a conveyor by an elevator and, after rotation of the turret plate through 180.degree., insert the unwound armature into a winding machine collet. After the winding of the armature is completed, the armature is again gripped by the gripping device and removed from the winding machine. Then, after the turret indexes through an additional 90.degree., the gripping device inserts the newly wound armature into a fusing machine after which the gripping device grips the newly wound and fused armature and retracts it from the fuser. The turret plate is indexed to return the wound and fused armature to the load station at which time the gripping device is extended to move the newly wound and fused armature onto the elevator which returns it to the conveyor. A conveyor and elevator such as the type disclosed in the aforementioned U.S. Pat. No. 4,982,827 has been used for this purpose. The turreted winding and fusing machine was of the type sold by The Globe Tool and Engineering Company of Dayton, Ohio, a predecessor of the assignee of the present invention, under its model designation MDF 6000.
Another example of the use of a rotating turret plate for handling armatures is disclosed in U.S. Pat. No. 4,087,054. In this case the turret plate carries two gripping mechanisms mounted on sliders and driven between retracted positions near the center of the turret plate and extended positions near the ends of the turret plate. The turret plate reversely rotates through successive 180.degree. increments to position the gripping mechanisms in confronting relation alternately to a pallet and to an armature winder. When extended, the gripping mechanisms either remove armatures from or insert armatures into the pallet or the armature winder. The gripping mechanisms of U.S. Pat. No. 4,087,054 include collets and shields which are used at the winding station to assist in the winding of the armatures.
In another prior art manufacturing line sold by The Globe Tool and Engineering Company, an unwound armature, which has rolled down along an inclined supply track to a pick-up point to the right of an armature winder, is clamped by a clamp assembly carried by a pivoting arm and, following pivotal movement of the arm, inserted into the armature winder. The pivoting arm is pivoted back to pick up the next unwound armature at the bottom of the track. After the winding is completed, a second transfer mechanism having two grippers transfers the wound armature from the winder to a fuser located above and to the left of the winder, and simultaneously transfers a wound and fused armature to a chain conveyor having a load station located adjacent the fuser.
Various armature manufacturing systems using pallets for carrying armatures to different processing stations have been used. An example of such a system, which also includes an armature loading and unloading apparatus, is shown in the aforementioned U.S. Pat. No. 5,372,319.